Jordan has declared borders with Syria and Iraq closed military zones after a car bomb exploded along Jordan's border with Syria on Tuesday, killing six soldiers and wounding 14 others.
Military officials also said no new refugee camps would be built in Jordan, and that no existing ones would be expanded.
The blast happened in the Rukban area where tens of thousands of people fleeing the violence in Syria have sought refuge as they try to get into Jordan.
There was no immediate claim of responsibility for the attack. Jordan's army said it destroyed several other vehicles that were involved, but did not provide more details.
U.S. State Department spokesman John Kirby condemned the attack in Jordan Tuesday.
“We condemn, in the strongest terms, this morning's attack in Jordan," Kirby said, also extending condolences to the victims' families. “The U.S. is committed to providing security assistance to Jordan, and we'll continue to cooperate closely in the wake of this attack. Jordan has already made tremendous sacrifices in hosting hundreds of thousands of Syrian refugees.”
The United Nations has already registered more than 650,000 refugees in Jordan. The nation of 8 million people is hosting many more than that and like other countries bordering Syria has struggled to cope with the added strain of providing for so many extra people.
U.N. appeals for aid money have fallen far short of their goals.
Nike Ching contributed to this report from the State Department.